The present invention relates to servo systems and more particularly to a circuit for enabling servo system to perform automatic system recovery and the method therefor.
Circuit of a conventional servo system for enabling the servo system to perform an automatic system recovery is disadvantageous for being high in design and manufacturing costs. Thus such circuit is not popular among low level and inexpensive servos. Typically, the conventional servo is restarted manually to reset the servo system when there is an abnormal termination of the servo system. This is unreliable and quite inconvenient. Thus improvement exists.
It is therefore an object of the present invention to provide a timer and associated circuit in the mainboard of servo such that servo system can transmit a signal representing system normal to the timer every predetermined period of time. Once servo system is abnormally terminated resulting in an interruption of the normal signal, the timer is triggered to generate a reset signal for restarting servo so as to complete the reset process of the system. This is an automatic system recovery process without any manual operation involved.
In one aspect of the invention, there is provided a transistor and a diode both being electrically coupled to the timer such that the signal received by the trigger pin of the timer is kept at a low level for avoiding from triggering the timer during normal servo system operation and when the connected power supply is stable.
In another aspect of the invention, there is provided a monitor circuit being electrically coupled to the timer such that a reset signal is only generated in the timer when the connected power supply is stable for preventing an erroneous reset from occurring in the servo system when the connected power supply is not stable.
In still another aspect of the invention, there is provided a register such that a high level reset signal outputted from the output pin of the timer is stored in the register for subsequent error recognition when system is abnormally terminated.
The above and other objects, features and advantages of the present invention will become apparent from the following detailed description taken with the accompanying drawings.